Uskottavuusvälejä

Uskottavuusvälejä, known in English as credibility intervals, are a concept used in statistics and research to quantify the uncertainty surrounding an estimate of a population parameter. Unlike traditional confidence intervals, which focus on the reliability of the estimation procedure, credibility intervals are derived using Bayesian statistical methods. The interpretation of a credibility interval is more direct: it represents a range within which the true parameter value is believed to lie with a certain probability. For example, a 95% credibility interval for a population mean means that there is a 95% probability that the true mean falls within that specific interval, given the observed data and the prior beliefs incorporated into the model.

The calculation of credibility intervals involves combining prior knowledge about the parameter with the information obtained from the data. This prior knowledge is expressed as a probability distribution, which is then updated using Bayes' theorem to produce a posterior distribution for the parameter. The credibility interval is then derived from this posterior distribution, typically as a range that contains a specified percentage of the posterior probability. The width of the credibility interval reflects the degree of uncertainty: a narrower interval suggests a more precise estimate, while a wider interval indicates greater uncertainty. This Bayesian approach allows for a more intuitive interpretation of the results, as it directly addresses the probability of the parameter's value itself.